As robots evolve, homes will need fewer R2-D2s and more C-3POs. Which one would you rather have cooking your dinner—a bleeping trash can or a tall shiny-metal figure with arms and legs?

Dozens of robots turned up at the CES 2018 tech show in Las Vegas. If you spotted a humanoid robot, especially one with legs, it was probably a toy. The larger, more useful robots were mostly on wheels, with short, stocky bodies. These guys are designed and programmed to patrol parking lots, deliver room service, greet shoppers. They’re close...